The influorescence meristems of the plant arabidopsis thaliance, undergo a global proliferative arrest. A unified arrest implies a signaling system may be involved. We wish to determine the nature of this global proliferative arrest. Are the meristematic cells held in Gl, G2, or a combination of the two? This will be determined by measuring nuclear DNA content in individual cells of arrested meristem tissue. We will look at the four zones (rib meristem, two lateral, and the dome) to determine if cells arrest in different stages depending on where they occur in the meristem.